World number one Roger Federer has pulled out of next week's Japan Open due to fatigue.

Federer, who won the Tokyo title last year, said he had yet to recover after winning his fourth consecutive US Open title and playing for Switzerland in the Davis Cup earlier this month.

"I am so disappointed that I have to withdraw from the Japan Open," Federer said in a statement.

"At this point I have still not physically recovered 100 percent from the US Open and Davis Cup.

"Thus my doctor advised me that in an effort to avoid the risk of serious injury, I should not play a tournament for at least 10 days."

Federer's late pullout for the October 1-7 Japan Open leaves world number eight David Ferrer as the tournament's highest seed following the Spaniard's late entry into the men's draw.

Wimbledon champion Venus Williams was also added to the women's draw on Friday.